\begin{figure}[htb]
	\centering
	\begin{pdfpic}
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	\psline[linewidth=0.04cm](1.2570118,2.0435157)(1.8570117,0.8835156)
	\psline[linewidth=0.04cm](2.8970118,1.7835156)(2.2370117,0.9435156)
	\psline[linewidth=0.04cm](2.3370118,0.58351564)(3.7570117,0.52351564)
	\psline[linewidth=0.04cm](0.43701172,1.1635156)(1.6570117,0.64351565)
	\psline[linewidth=0.04cm](0.43701172,1.1635156)(1.6570117,-0.43648437)
	\psline[linewidth=0.04cm](0.65701175,-1.7364844)(1.7770118,-0.79648435)
	\psline[linewidth=0.04cm](2.3170118,-1.8764844)(2.0570116,-0.9364844)
	\psline[linewidth=0.04cm](3.5970118,-1.1364844)(2.4170117,-0.7564844)
	\psline[linewidth=0.04cm](2.3570118,0.34351563)(3.5970118,-1.1364844)
	\psline[linewidth=0.04cm](0.15701172,-0.31648436)(1.5570117,-0.59648436)
	\psline[linewidth=0.04cm](1.9370117,0.38351563)(1.9970117,-0.35648438)
	\pspolygon[linewidth=0.04](7.1570115,2.0635157)(8.797011,1.8035157)(9.657012,0.5435156)(9.497012,-1.1164844)(8.217011,-1.8564844)(6.5570116,-1.7164844)(6.0570116,-0.29648438)(6.337012,1.1835157)
	\psline[linewidth=0.04cm](7.1570115,2.0635157)(7.797012,0.58351564)
	\psline[linewidth=0.04cm](8.797011,1.8035157)(8.017012,0.52351564)
	\psline[linewidth=0.04cm](8.257011,0.16351563)(9.657012,0.5435156)
	\psline[linewidth=0.04cm](6.337012,1.1835157)(7.4770117,0.3035156)
	\psline[linewidth=0.04cm](6.5570116,-1.7164844)(7.6170115,-0.37648436)
	\psline[linewidth=0.04cm](8.217011,-1.8564844)(7.9970117,-0.43648437)
	\psline[linewidth=0.04cm](8.197012,-0.17648438)(9.497012,-1.1164844)
	\psline[linewidth=0.04cm](6.0570116,-0.29648438)(7.4570117,-0.056484375)
	\usefont{T1}{ptm}{m}{n}
	\rput(2.015254,0.64851564){$v_u$}
	\usefont{T1}{ptm}{m}{n}
	\rput(1.975791,-0.61148435){$v_t$}
	\usefont{T1}{ptm}{m}{n}
	\rput(0.13183594,1.2485156){$v_l$}
	\usefont{T1}{ptm}{m}{n}
	\rput(3.8066015,-1.2914844){$v_r$}
	\usefont{T1}{ptm}{m}{n}
	\rput(7.8492384,0.10851563){$v_s$}
	\usefont{T1}{ptm}{m}{n}
	\rput(6.011836,1.3685156){$v_l$}
	\usefont{T1}{ptm}{m}{n}
	\rput(9.766602,-1.2514844){$v_r$}
	\psline[linewidth=0.04cm,arrowsize=0.05291667cm 2.0,arrowlength=1.4,arrowinset=0.4]{->}(3.6370118,1.9435157)(6.1570115,1.9435157)
	\psline[linewidth=0.04cm,arrowsize=0.05291667cm 2.0,arrowlength=1.4,arrowinset=0.4]{<-}(3.6370118,-1.8964844)(6.1570115,-1.8964844)
	\usefont{T1}{ptm}{m}{n}
	\rput(4.8928905,2.2285156){$ecol(v_s,v_t,v_u,v_l,v_r)$}
	\usefont{T1}{ptm}{m}{n}
	\rput(4.878076,-2.1914845){$vsplit(v_s,v_t,v_u,v_l,v_r)$}
	\end{pdfpic} 
	\caption{Edge collapse and vertex split transformations}
	\label{fig:ecol_vsplt_illustration}
\end{figure}